Art of making castings.



C. M. GREY.

ART OF MAKING GASTINGS.

APPLICATION FILED JANA, 1912.

Patented 001;. 6, 1914.

Saddam Sucfi'o n or Press are [NVE/VTOR Ufiarzes M67151 WITNESSES I Altorneys CHARLES M. GREY, OF EAST ORANGE, NEW JERSEY.

' ART OF MAKING CASTINGS.

Specification of Letters Patent.

Patented Oct. c, late.

Application filed January 4, 1912. Serial No. 669,351.

To all whom it may concern Be it known that I, CHARLES M. GREY, a citizen of the United States, residing at East Orange, county of Essex, and State of New Jersey, have invented a certain new and useful Art of Making Castings, of which the following is a specification.

This invention is a method of making castings, particularly die castings, and the objects of the invention broadly stat-ed, are two-fold; first, to minimize the quantity of air or gases in the die for the purpose of producing castings substantially free from blow holes, or entrained air or gases, and, second. to produce castings which are substantially free from oxidized metal.

WVith the specified objects in view, the invention consists in precluding the admission into the die, in whole or in part, of the air or gases which may be confined in the passages or chambers intermediate the metal reservoir and the die, just prior to introducing the metal into the die, and, also, precluding the introduction into the die of any oxidized metal which may be contained on the surface of the metal as it flows from the metal reservoir to the die.

Notwithstanding it has been heretofore proposed in making die castings to produce a partial vacuum in the die, and in the passage leading from the metal reservoir to the die, experience shows that a considerable volume of air is apt to remain in the said passage, and, consequently, is forced, during the casting operation into the die. The metal is forced into the die under high pressure, and, consequently, moves very rapidly, the effect of this movement being to more or less compress the air or gases in the said passage, the flowing metal acting as a piston, and to force saidgases into the die so rapidly that they do not have an opportunity to escape therefrom. Accordingly, they become entrained into the casting, resulting in a more or less cellular product. The novel method herein set forth overcomes this disadvant. e in that the air or gas compressed. by the owing metal is precluded from entering the die.

It is well recognized that when metals are in a molten condition, particularly alloys containing zinc, they become readily oxidized, and in the present methods of die casting the film of oxid which exists on the surface of the metal in the metal reservoir finds its way into the die, thereby resulting in a casting containing oxidized metal, which, of course, is a pronounced disadvantage. The

process of this application obviates this dis- I Figure 1 is a sectional elevation of a suit able form of apparatus wherein the molten metal is in a condition to be forced into the due according to the method of the present invention. Fig. 2 is a detail view illustrating the metal flowing into the die and partly filling a chamber above the inlet passage to said die.

A designates a bed upon which is adapted to rest a die B, the latter having a cavity 7) for receiving molten metal from a reservoir or melting pot C. As shown, the melting pot or reservoir is substantially U-shaped,

the same having chambers c, 0 connected by an intermediate chamber 0 One leg of the U-shaped melting pot, z. e., the leg containmg the chamber c', is in the form of a nozzle 0 adapted to supply the molten metal to a passage D through which the metal is adapted to flow to the inlet or inlet passage 0 leading into the cavity 6 of die B.

As shown, suitable means are provided for exhausting air from the die, said means be- -ing a suction pipe E leading to a suitable exhauster, said suction pipe communicating with a chamber e provided in die B exteriorly of die cavity Z) and communicating therewith through an intermediate pa sage 2 F designates a chamber in communication with passage D and positioned above the inlet or inlet passage 6 to the die. This chamber is designed to receive the air compressed in passage D by the movement of the metal as it flows toward the inlet 6 to the die, and in addition to the air thus compressed Within the chamber F, said chamber receives the oxidized metal on the surface of the molten metal, whereby unoxidized metal is permitted to flow through passage 6 into the die cavity.

' tlhamber l is provided in a member Gr coiiperating with the die, said member G duce chamber 1F and in t e position of the parts shown in the drawings, the chambered gate or piston G is above the horizontal plane or the inlet passage e. Chamber F opens through the lower end of member Gr so asto communicate freely with passage D. W hen the member G is to be used as a gate or piston, suitable operating means are associated therewith for imparting reciprotill till

cating movement to said member G, and, as shown, a lever g is connected by a pivot pin 9" to the upper part of member G, said member eatendmg exteriorly to the die and above the same. B operating lever g, the member G may be owcred so as to cut ed the flow of metal from passage D to the die inlet e, and said member Gr may be depressed by operating said lever 9' so as to force the molten metzil back into the reservoir or melting pot after the required quantity of metal shall have been supplied to the die.

With member Gr is associated suitable means for exhausting air from chamber l passage D, and chamber a in the nozzle of the molten metal reservoir, said exhausting means being shown as a pipe h leading to a suitable enhauster. Said pipe it may be in the form of a flexible hose, and it communicates with chamber F by a passage it provided in member G.

buitable means are provided for exerting pressure upon the molten metalin reservoir C, and as shown in Fig. l, a pipe H is coupled to one leg of the melting pot for com munication with the chamber 0 therein. Air or gas under suitable pressure is adapted to be supplied by a pipe H from any suitable source, and at the required time, for imparting movement to the molten metal in reservoir C for the purpose of securing the flow of metal toward the die. Said pipe H is adapted, also, for communication with means for'exhausting air from the pipe and from chamber 0 of the U-shaped reservoir, so that air will be exhausted from the chamher 0 as well as from chamber 0 of the reservoir, in order to keep the mass of molten metal in a quiescent condition and thereby restrain the molten metal from flowing toward the die, whereby the em loyment of a valve for shutting ofi the fi ow of metal from the reservoir to the die is obviated.

When using the apparatus metal is kept in a molten condition by well known means,

and air is exhausted from the die by pipe D, from chamber is by pipe ill, and from chamber a, passage D, and chamber it, by pipe 7?. whereby the molten metal is precluded from flowing from the melting pot throu h passage D to the die. The exposure of mo ten metal in chamber 0' to air results in the oxidation of the metal at the top of the charge of molten metal, and'notwith' standing that air is exhausted from cham here a, F, and passage D, as well as from the die cavit a certain quantity of air still remains in t e aforesaid chambers and passage way.

By applyin pressure to the molten metal in reservoir as by admitting air or gas by pipe H to chamber 0, the metal is moved rapidly in the receptacle and through nozzle 0 and passage way D. The sudden movement 0 the molten metal due to the application of ressure thereto impels some of the metal t rough the passage way D, the metal flowing upwardly into the lower part of chamber l? so that the oxidized metal at the surface of the molten metal will be received in chamber F and be above the inlet passage 6 to the die. The movement of the metal by applying pressure thereto takes place very quickly, and as a result, the air present in the assage way D is precluded from entering t e die and is collected or received within chamber F. The size of said chamber is such that the air compressed by the movement of the metal as it flows toward the die will not be compressed u to atmospheric pressure.

From tie foregoing it will be understood that as pressure is applied to the metal to move it toward the die, the movement oi the mass of metal compresses the air in passage way D and chamber 0 so that the air is forced past the die inlet e and is collected within chamber F. lt'will be understood that the air compresscd in this chamber l is drawn oil through the suction pipe it. Simultaneously with this operation ofcompressing the air so as to preclude it from admission to the die, the oxidized lltltl metal on the surface of the molten metal I is lifted above the die inlet and received within the lower part of chamber F as indicated in Fig. 2, whereby unoxidized metal will flow from the molten metal through die inlet 6 and into the die cavity.

lllti After the casting operation shall have been completed, member Gr may be lowered by operating lever 9 so as to move past the die inlet e, thus acting as a gate, and such downward movement of member (3- will force the metal from passage D back into the reservoir. The sprue fills the inlet passage c and may be removed in the usual way.

It will be obvious that if the flow of metal from the reservoir is in a horizontal direction. instead of vertically as herein illustrated, that a slight change in the arliltl rangement of the collecting chamber will be necessary.

Having thus fully described the inven* tion, what I claim as new, and desire to secure by Letters Patent is 1. In the art of making die castingis, the improvement which consists in intro ucing metal from a reservoir into the die and utilizing the flow of metal to compress the air or gases and to force the same into a chamber separate from the die.

2. In the art of making die castings, the improvement which consists in forcing metal from a reservoir into the die and utilizing the How of the metal to compress the air or gases and to force the same into a chamber separate from the die.

3. In the art of making die castings, the improvement which consists in forcing metal from a reservoir into the die and simultaneously exhausting air forwardly of the flowing metal prior to 1t s entrance into the die throu h a passage separate from the die.

4. In the art of making die castings, the improvement which consists in forcing metal from a reservoir into the die, exhausting air forwardly of the flowing metal prior to its entrance into the die through a passage separate from the die, and utilizing the flow of the metal to compress the air or gas and to force the same into the separate passage.

5. In the art of making die castings, the improvement which consists in forcing the metal from the metal reservoir toward the die by applying pressure to the metal in said reservoir, whereby the oxid on the surface of said metal is driven by and beyond the inlet to the die, and unoxidized metal, only, is forced into the die.

6. In the art of making die castings, the

improvement which consists in forcing metal from the metal reservoir toward the die, and introducing metal into the die from 7. In the art of making die castings, the

process which consists in simultaneously precluding the entrance into the die of air or gases contained in a passage connecting a metal reservoir with the die and of the oxidized metal contained on the surface of the metal flowing into the die.

8. In the art of making" die castings, the process'which consists in forcing metal from a metal reservoir towardthe die, and in directing the air or gases contained in the passage between said reservoir and the die, and, also, the metallic oxid carried by the current of metal, into a passage separate from the die, whereby said air or gases and the oxidized metal are precluded from entering the die.

9. In the art of making die castings, the process which consists in forcing metal from a metal reservoir toward the die, and in collecting the air or gases contained in the passage between said reservoir and the die, and, also, the metallic oxid carried by the currentof metal, into a vacuum chamber separate from the die, whereby said air or gases and the oxidized metal are precluded from entering the die.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

CHARLES M. GREY.

Witnesses:

J. F. MOTHERSHEAD, M. E. FREEMAN. 

